Martin Ryle, a graduate of Bradfield College and the University of Oxford, helped develop radar countermeasures for British defense while working at the Telecommunications Research Establishment during World War II. Afterward, at the University of Cambridge, he was a leader in the development of radio astronomy. With his aperture synthesis technique of interferometry he and his team located radio-emitting regions on the sun and pinpointed other radio sources so that they could be studied in visible light. Ryle’s 1C to 5C Cambridge catalogues of radio sources led to the discovery of numerous radio galaxies and quasars. Ryle’s counts of radio sources versus brightness supported evolving universe cosmologies, and he became a leading opponent of the steady state model proposed by H. Bondi, T. Gold, & F. Hoyle. Ryle’s development of earth rotation synthesis and construction of radio interferometers up to 5 km long eventually allowed radio astronomers to surpass optical astronomers in angular resolution. The first professor of radio astronomy in Britain, he was an influential member of many boards and committees involved in the organization of British astronomy, and he served as Astronomer Royal for a decade. In his later years he encouraged alternative sources of energy, designing a new wind generator with his students, and he spoke out in opposition to nuclear power and nuclear weapons.